This invention relates to a method and an apparatus for feeding a liquid crystal.
As is known, a liquid crystal display unit is constituted by filling a liquid crystal in a container having a thin internal space. As disclosed in Japanese Laid-Open Patent Application No. 62-141516, according to a typical method for feeding a liquid crystal, air contained in an internal space of a container is discharged from an air discharge port to evacuate the container, and then a liquid crystal is fed into the internal space through a feed port of the container. The liquid crystal thus fed is filled in the container owing to the effect of a vacuum drawing operation and capillary action. However, since this method requires a vacuum drawing apparatus, the costs for manufacturing the liquid crystal display unit are high. It also has the shortcomings that due to vacuum drawing, a solvent, etc. contained in the liquid crystal are susceptible to volatilization, and therefore viscosity of the liquid crystal is increased, and eventually the time for filling the liquid crystal is increased.
In order to overcome the above shortcomings, the present inventor has developed a method for feeding a liquid crystal, in which a liquid crystal is fed by a centrifugal force and by a compression air pressure in accordance with necessity, through a feed port of a container while opening an air discharge port of the container to the atmosphere (Japanese Laid-Open Patent Application No. 6-82740 laid open Mar. 25, 1994). However, this method still has the shortcomings that in the case where the internal space of the container is made so thin as several .mu.m (for example, 3 .mu.m), air bubbles remain in the container. Specifically, as shown in FIG. 6, a liquid crystal L fed in the internal space of the container is caused to have a plurality of tentacles or fingers La by capillary action. When the fingers La are branched and grown to unite adjacent fingers La, air bubbles remain between the adjacent fingers La. Attention should be paid to the fact that according to this method, an acting direction of the centrifugal force is the same to a proceeding direction of a leading edge of the liquid crystal in the container.